Various mobile architectures include a macro cell having smaller cells found within these macro cells. One example is a Long Term Evolution Advanced (LTE-A) communication standard in which a User Equipment (UE) may communicate with both the macro cell and small cells, such as pico cells, femto cells or relay cells. The use of LTE-A is however not limiting, and any other similar networks are possible.
In an LTE heterogeneous network, pico cells could be deployed with overlaid macro cells. The pico cells could share the same carrier with the macro cell or use different carriers. A network may offload traffic from an aggressor cell such as the macro cell to a victim cell having a weaker signal than the aggressor cell in order to free network resources.
If an aggressor cell is producing significant interference for a victim cell that is trying to send a system information message, referred to herein as a page, to the UE, it may be difficult or impossible for the UE to detect the page unless the page coincides with an almost blank subframe (ABS) of an aggressor cell. The UE, however, only listens for pages during a UE's paging occasion (PO) and thus the UE may be unable to receive a page unless the PO corresponds with the ABS of the aggressor cell. In some cases, this can be quite long or never. For example, when a victim UE is attached to a pico cell, the UE may be paged by the Evolved Node-B (eNB). In the presence of macro cell interference, particularly when the pico UE is operating in cell range expansion, the page may be missed. While the disclosure below discusses a pico/macro scenario, other cases where cell interference can lead to a weaker cell's pages being missed are also possible and the present solution is not limited to such a pico and macro scenario.
The terms “aggressor” and “victim” cell are used herein to describe cells having a stronger signal and a weaker signal, as viewed by a UE, respectively. In some cases, this may correspond to Release 10 LTE definitions, which describe cells in specific scenarios, regardless of signal strength, and imply that the aggressor may use ABS. For example, the macro cell is the aggressor cell in macro-pico scenario in LTE release 10. However, in other cases such as a macro-macro scenario, aggressor and victim cells are not defined by release 10 LTE. Thus, as used herein, the aggressor cell is defined as the cell from which the strongest downlink signal is received, and victim cell or cells are those with weaker received downlink signals at the time of camping selection. An aggressor cell and one or more victim cells can be identified for each UE where two or more cells exist. Further, signal strengths of the cells may change as viewed at a UE, and thus a victim cell may become an aggressor cell, and vice versa.